The ratios of the production cross sections between the excited $\Upsilon$(2S) and $\Upsilon$(3S) mesons and the $\Upsilon$(1S) ground state, detected via their decay into two muons, are studied as a function of the number of charged particles in the event. The data are from proton-proton collisions at $\sqrt{s} =$ 7 TeV, corresponding to an integrated luminosity of 4.8 fb$^{-1}$, collected with the CMS detector at the LHC. Evidence of a decrease in these ratios as a function of the particle multiplicity is observed, more pronounced at low transverse momentum $p_\mathrm{T}^{\mu\mu}$. For $\Upsilon$(nS) mesons with $p_\mathrm{T}^{\mu\mu}$ $\gt$ 7 GeV, where most of the data were collected, the correlation with multiplicity is studied as a function of the underlying event transverse sphericity and the number of particles in a cone around the $\Upsilon$(nS) direction. The ratios are found to be multiplicity independent for jet-like events. The mean $p_\mathrm{T}^{\mu\mu}$ values for the $\Upsilon$(nS) states as a function of particle multiplicity are also measured and found to grow more steeply as their mass increases.
The measured ratios $\Upsilon(2$S$)\,/\,\Upsilon(1$S$)$ and $\Upsilon(3$S$)\,/\,\Upsilon(1$S$)$ with $p_T(\Upsilon(n$S$))>7\,GeV$ and $|y(\Upsilon(n$S$))| < 1.2$, as a function of track multiplicity $N_{track}$
The measured ratios $\Upsilon(2$S$)\,/\,\Upsilon(1$S$)$ and $\Upsilon(3$S$)\,/\,\Upsilon(1$S$)$ with $p_T(\Upsilon(n$S$))>0\,GeV$ and $|y(\Upsilon(n$S$))| < 1.93$, as a function of track multiplicity $N_{track}$.
Mean $p_T$ values of the $\Upsilon(1$S$)$, $\Upsilon(2$S$)$, and $\Upsilon(3S)$ states with $p_T\,>\,7\,GeV$ and $|y|\,<\,1.2$ as a function of track multiplicity $N_{track}$
Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 inverse femtobarns. The W bosons are identified through their decay mode W to mu nu. The cross sections are reported as functions of jet multiplicity, transverse momenta, and the scalar sum of jet transverse momenta (HT) for different jet multiplicities. Distributions of the angular correlations between the jets and the muon are examined, as well as the average number of jets as a function of HT and as a function of angular variables. The measured differential cross sections are compared with tree-level and higher-order recent event generators, as well as next-to-leading-order and next-to-next-to-leading-order theoretical predictions. The agreement of the generators with the measurements builds confidence in their use for the simulation of W+jets background processes in searches for new physics at the LHC.
The cross section measurement as a function of the exclusive jet multiplicity, for jet multiplicities of up to 7.
The cross section measurement as a function of the exclusive jet multiplicity, for jet multiplicities of up to 7.
The cross section measurement as a function of the inclusive jet multiplicity, for jet multiplicities of up to 7.
The total cross section for γγ→hadrons was measured as a function of the invariant massW of the system (1.25 to 4.25 GeV) at thee+e−-collider VEPP-4 with the detector MD-1. For the first time the data were obtained by detecting both scattered leptons with almost zero emission angles. The mean squared four momentum transfer 〈q2〉 is −0.005 GeV2, the rmsW resolution is 100–250 MeV. The data on the mean charged multiplicity 〈nC〉 are well described by the function 〈nC〉=(1.62 ±0.37)+(1.83±0.45)·ln(W(GeV)). TheW dependence of the total cross section is consistent with the theoretical prediction σ(nb)=240+270/W(GeV).
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A nuclear photographic emulsion method was used to study the charge-state, ionization, and angular characteristics of secondaries produced in inelastic interactions of 56 Fe nuclei at 1.8 GeV/nucleon with H, CNO, and AgBr nuclei. The data obtained are compared with the results of calculations made in terms of the Dubna version of the cascade evaporation model (DCM). The DCM has been shown to satisfactorily describe most of the interaction characteristics for two nuclei in the studied reactions. At the same time, quantitative differences are observed in some cases.
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NUCLECS IS CNO.
The elastic and topological p¯p cross sections have been measured at 48.9 GeV/c in the Fermilab proportional-wire-chamber-30-in.-bubble-chamber hybrid spectrometer. The elastic cross section is 7.81±0.24 mb and the slope of the elastic differential cross section at t=0 is 13.4±0.8 GeV−2. Further, the moments of the inelastic topological-cross-section distribution are 〈nc〉=5.69±0.03, 〈nc〉D=2.10±0.02, and f2cc=1.67±0.12.
Axis error includes +- 0.0/0.0 contribution (?////DALITZ PAIRS. VEES AND GAMMA CONVERSIONS NEAR THE VERTEX WERE DETERMINED TO BE NEGLIGIBLE. LOW -T ELASTIC EVENTS//ODD-PRONG EVENTS APPARANTLY NOT CAUSED BY SECONDARY INTERACTIONS WERE MOVED TO THE NEXT HIGHER MULTIPLICITY ON THE ASSUMPTION THAT A SHORT TRACK WAS NOTVISIBLETOTAL AP-P CROSS SECTION OF 43.86+-0.25 MB FROM A.S.CARROL ET AL.PRL 33, 928(1974) WAS USED FOR NORMALIZATION).
Axis error includes +- 0.0/0.0 contribution (?////DALITZ PAIRS. VEES AND GAMMA CONVERSIONS NEAR THE VERTEX WERE DETERMINED TO BE NEGLIGIBLE. LOW -T ELASTIC EVENTS//ODD-PRONG EVENTS APPARANTLY NOT CAUSED BY SECONDARY INTERACTIONS WERE MOVED TO THE NEXT HIGHER MULTIPLICITY ON THE ASSUMPTION THAT A SHORT TRACK WAS NOTVISIBLETOTAL AP-P CROSS SECTION OF 43.86+-0.25 MB FROM A.S.CARROL ET AL.PRL 33, 928(1974) WAS USED FOR NORMALIZATION).
No description provided.
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